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implement SSU2HolPunchSession

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orignal 2024-10-16 08:28:25 -04:00
parent ec1f41b13c
commit 97fdedfbe3
5 changed files with 88 additions and 49 deletions
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58
libi2pd/SSU2OutOfSession.cpp
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@ -224,5 +224,63 @@ namespace transport
m_NumResends++;
}
}
SSU2HolePunchSession::SSU2HolePunchSession (SSU2Server& server, uint32_t nonce,
const boost::asio::ip::udp::endpoint& remoteEndpoint,
std::shared_ptr<const i2p::data::RouterInfo::Address> localAddr):
SSU2Session (server), // we create full incoming session
m_Nonce (nonce)
{
// we are Charlie
m_Token = GetServer ().GetIncomingToken (remoteEndpoint);
uint64_t destConnID = htobe64 (((uint64_t)nonce << 32) | nonce); // dest id
uint32_t sourceConnID = ~destConnID;
SetSourceConnID (sourceConnID);
SetDestConnID (destConnID);
SetState (eSSU2SessionStateHolePunch);
SetRemoteEndpoint (remoteEndpoint);
SetAddress (localAddr);
SetTerminationTimeout (SSU2_RELAY_NONCE_EXPIRATION_TIMEOUT);
}
void SSU2HolePunchSession::SendHolePunch ()
{
auto addr = GetAddress ();
if (!addr) return;
auto& ep = GetRemoteEndpoint ();
LogPrint (eLogDebug, "SSU2: Sending HolePunch to ", ep);
Header header;
uint8_t h[32], payload[SSU2_MAX_PACKET_SIZE];
// fill packet
header.h.connID = GetDestConnID (); // dest id
RAND_bytes (header.buf + 8, 4); // random packet num
header.h.type = eSSU2HolePunch;
header.h.flags[0] = 2; // ver
header.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID
header.h.flags[2] = 0; // flag
memcpy (h, header.buf, 16);
htobuf64 (h + 16, GetSourceConnID ()); // source id
RAND_bytes (h + 24, 8); // header token, to be ignored by Alice
// payload
payload[0] = eSSU2BlkDateTime;
htobe16buf (payload + 1, 4);
htobe32buf (payload + 3, (i2p::util::GetMillisecondsSinceEpoch () + 500)/1000);
size_t payloadSize = 7;
payloadSize += CreateAddressBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize, ep);
payloadSize += CreateRelayResponseBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize,
eSSU2RelayResponseCodeAccept, m_Nonce, m_Token, ep.address ().is_v4 ());
payloadSize += CreatePaddingBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize);
// encrypt
uint8_t n[12];
CreateNonce (be32toh (header.h.packetNum), n);
i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, h, 32, addr->i, n, payload, payloadSize + 16, true);
payloadSize += 16;
header.ll[0] ^= CreateHeaderMask (addr->i, payload + (payloadSize - 24));
header.ll[1] ^= CreateHeaderMask (addr->i, payload + (payloadSize - 12));
memset (n, 0, 12);
i2p::crypto::ChaCha20 (h + 16, 16, addr->i, n, h + 16);
// send
GetServer ().Send (header.buf, 16, h + 16, 16, payload, payloadSize, ep);
}
}
}